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1.
Indian J Surg Oncol ; 15(2): 250-257, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38741650

ABSTRACT

Molecular sub-characterization of triple-negative breast cancer (TNBC) has great therapeutic and possibly prognostic implications. The primary aim of this study was to investigate the incidence of luminal androgen receptor (LAR) subtype of TNBC and secondary aims were sub-categorization and clinico-pathologic correlation of LAR breast cancers. Retrospective study (January 2008 and 31st of December 2018) consisting of 157 TNBC patients. Androgen receptor (AR) expression was measured by immunohistochemical analysis. One percent cutoff was set as a positive expression. Sub-categorization was done on the basis of EGFR (> 15% of tumor cells) and Ki-67 expression (low- < 11%, intermediate- 11-20%, and high- > 21%). AR expression was correlated with various clinico-pathologic features and outcomes of the patients. The incidence of AR expression in TNBC was 24.8%. Considering different thresholds of > 5%, > 10%, and > 20% immunostaining, the incidence of AR positivity was 18.4, 15.2, and 11.5% respectively. The incidence of Ki-67 (p = 0.89) and EGFR (p = 0.643) expression did not differ significantly in AR-positive and -negative TNBC. Based on EGFR expression 19, 67 and 14% patients were categorized as low, intermediate, and high risk respectively. Low-risk (p ≤ 0.001) and low-grade (p = 0.014) tumors were more likely to have > 10% AR expression. Clinico-pathological profile, response to neoadjuvant chemotherapy, disease-free survival (p = 0.458), and overall survival (p = 0.806) did not significantly differ between AR expressing and negative TNBC. On multivariate analysis, only tumor staging was a significant predictor of survival (p = 0.012) and AR expression of > 10% revealed a trend towards improved survival (p = 0.07). When considering only AR-positive TNBC, AR expression of > 10% (p = 0.038), distant metastases (p = 0.003), and EGFR status (p = 0.024) were significantly associated with survival. AR expression does not seem to very strongly correlate with prognosis in TNBC and further studies could focus more on its predictive role in deciding anti-androgen therapy.

2.
J Lab Physicians ; 15(3): 344-353, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37564228

ABSTRACT

Objectives Methotrexate (MTX) has anticancer therapeutic potential with multiple doses-related adverse effects and toxicities. Immunoassays for therapeutic monitoring of serum MTX have their own limitations. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is considered as the reference method; however, commercially availability of them is limited. We aimed to adapt/develop an in-house LC-MS/MS method for therapeutic monitoring of serum MTX. Materials and Methods Serum protein precipitation was performed using acetonitrile-water containing 250 µM solution of aminoacetophenone as internal standard (IS). Chromatographic separation was achieved on a C18 column with mobile phase of 0.1% solution of formic acid (solvent A) and acetonitrile (solvent B) at a flow rate of 0.4 mL/min. MS was performed under positive ion mode with mass transition for MTX and IS as m/z 455.1→308.1 and 136.2→94.1, respectively. The method was validated by following Bioanalytical Method Validation Guidance for Industry, 2018 and applied on leukemia patients' samples on MTX therapy. Results The correlation coefficient of eight serially diluted calibration standards of 0.09 to 12.5 µM was >0.99 and had linearity with > 95% precision and accuracy at analytical quality control levels. The lower limit of MTX quantification achieved was 0.09 µM with good intensity and sharp peak as compared with blank sample. The total run time of the assay was 5 minutes. The serum MTX levels obtained by this method in leukemia patients exhibited clinical correlation and an excellent agreement with commercial immunoassay used in parallel. Conclusion We were able to develop a rapid, sensitive, and cost-effective LC-MS/MS method suitable for therapeutic drug monitoring of MTX in routine clinical diagnostic laboratories.

3.
FEBS Lett ; 597(3): 448-457, 2023 02.
Article in English | MEDLINE | ID: mdl-36480405

ABSTRACT

The ubiquitin-like protein Hub1/UBL-5 associates with proteins non-covalently. Hub1 promotes alternative splicing and splicing of precursor mRNAs with weak introns in yeast and mammalian cells; however, its splicing function has remained elusive in multicellular organisms. Here, we demonstrate the splicing function of Hub1/UBL-5 in the free-living nematode Caenorhabditis elegans. Hub1/UBL-5 binds to the HIND-containing splicing factors Snu66/SART-1 and PRP-38 and associates with other spliceosomal proteins. C. elegans hub1/ubl-5 mutants die at the Larval 3 stage and show splicing defects for selected targets, similar to the mutants in yeast and mammalian cells. UBL-5 complemented growth and splicing defects in Schizosaccharomyces pombe hub1 mutants, confirming its functional conservation. Thus, UBL-5 is important for C. elegans development and plays a conserved pre-mRNA splicing function.


Subject(s)
Caenorhabditis elegans Proteins , Saccharomyces cerevisiae Proteins , Schizosaccharomyces , Animals , RNA Precursors/genetics , RNA Precursors/metabolism , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Ubiquitins/metabolism , Saccharomyces cerevisiae/metabolism , RNA Splicing , Schizosaccharomyces/genetics , Schizosaccharomyces/metabolism , Mammals/genetics , Mammals/metabolism , Ligases/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism
4.
Nucleic Acids Res ; 50(17): 10000-10014, 2022 09 23.
Article in English | MEDLINE | ID: mdl-36095128

ABSTRACT

Intron diversity facilitates regulated gene expression and alternative splicing. Spliceosomes excise introns after recognizing their splicing signals: the 5'-splice site (5'ss), branchpoint (BP) and 3'-splice site (3'ss). The latter two signals are recognized by U2 small nuclear ribonucleoprotein (snRNP) and its accessory factors (U2AFs), but longer spacings between them result in weaker splicing. Here, we show that excision of introns with a BP-distant 3'ss (e.g. rap1 intron 2) requires the ubiquitin-fold-activated splicing regulator Sde2 in Schizosaccharomyces pombe. By monitoring splicing-specific ura4 reporters in a collection of S. pombe mutants, Cay1 and Tls1 were identified as additional regulators of this process. The role of Sde2, Cay1 and Tls1 was further confirmed by increasing BP-3'ss spacings in a canonical tho5 intron. We also examined BP-distant exons spliced independently of these factors and observed that RNA secondary structures possibly bridged the gap between the two signals. These proteins may guide the 3'ss towards the spliceosome's catalytic centre by folding the RNA between the BP and 3'ss. Orthologues of Sde2, Cay1 and Tls1, although missing in the intron-poor Saccharomyces cerevisiae, are present in intron-rich eukaryotes, including humans. This type of intron-specific pre-mRNA splicing appears to have evolved for regulated gene expression and alternative splicing of key heterochromatin factors.


Subject(s)
RNA Precursors , Schizosaccharomyces , Alternative Splicing , Carrier Proteins , DNA-Binding Proteins/genetics , Exons , Heterochromatin , Humans , Introns/genetics , Nuclear Proteins/metabolism , RNA Precursors/metabolism , RNA Splice Sites , RNA Splicing , Ribonucleoprotein, U2 Small Nuclear/genetics , Schizosaccharomyces/genetics , Schizosaccharomyces/metabolism , Schizosaccharomyces pombe Proteins , Shelterin Complex , Telomere-Binding Proteins , Ubiquitin/genetics , Ubiquitin/metabolism
5.
Iran J Microbiol ; 14(1): 104-111, 2022 Feb.
Article in English | MEDLINE | ID: mdl-35664720

ABSTRACT

Background and Objectives: In recent decades, the incidence of dengue has increased dramatically. In dengue-endemic countries, changes in dengue virus serotypes, genotypes, and lineages have been reported. This study was designed to detect and characterize the dengue virus isolates circulating in North India by serological and molecular techniques. Materials and Methods: This study was conducted at the Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India. NS1 antigen and IgM antibody against dengue were detected by ELISA methods, viral RNA was extracted and amplified by conventional PCR and one-step single-tube multiplex PCR. The purified PCR products were cycle sequenced and a database search was implemented for the confirmation of the sequence product. Phylogenetic analysis was carried out with previously reported sequences. Results: Among 1509 samples, 205 (13.6%) were found positive for IgM antibodies with the highest number (n=67) among the 21 to 30 years age group with peak positivity during post-monsoon months. Among acute samples, NS1 antigen was positive in 62.9%. Seven patients out of 13 had dengue viral RNA in PCR. It comprised six DENV-2 serotypes and one DENV-3 serotype. On phylogenetic analysis, DENV-2 strains grouped with genotype IV and DENV-3 with genotype III. Conclusion: Dengue infection was found frequently during post-monsoon season. The positivity rate of the dengue NS1 antigen test was greater than that of the antibody test. The dengue isolates were characterized as genotype IV and genotype III of DENV-2 and DENV-3 respectively.

6.
MicroPubl Biol ; 20222022.
Article in English | MEDLINE | ID: mdl-35098049

ABSTRACT

The conserved ubiquitin-like protein Hub1/UBL5 functions in RNA splicing, DNA repair and mitochondrial unfolding responses. It binds proteins specific to these pathways and modifies their functional properties. However, the identities of other Hub1 substrates remain unknown. We have found unreported interactors of Saccharomyces cerevisiae Hub1 from a yeast two-hybrid (Y2H) screen. Proteins containing SIMs (small ubiquitin-like modifier SUMO-interaction motifs) and ferulic acid decarboxylase Fdc1 are identified as potential Hub1 interactors. Further experiments are required to establish these interactions and their physiological relevance, nevertheless, data presented here point towards larger and intriguing roles of Hub1.

7.
Cancer Genet ; 258-259: 41-48, 2021 11.
Article in English | MEDLINE | ID: mdl-34455261

ABSTRACT

Ampulla is a complex region located at the confluence of pancreatic and common bile duct and intestinal epithelium. Tumors arising in this region are anatomically and morphologically heterogenous, however they show unique as well as overlapping molecular features. Cancers of both these anatomic sites share morphological as well as genetic profile despite having few unique differences. Targeted therapies are currently emerging as one of the demanding approaches for treatment in most cancer types especially for malignant epithelial tumors and therefore genetic profiling of cancers is the key for identification of potentially therapeutic targetable mutations to know their prevalence and prognostic impact. We studied 97 resected cases of formalin fixed paraffin-embedded AC by deep targeted sequencing using Ampliseq cancer hotspot panel comprising of 50 oncogenes and tumor suppressor genes. Potentially therapeutic targetable mutations were observed in 58/83 (70%) cases. Fourteen patients did not show any pathogenic mutation. TP53 (48.1%), KRAS (37.3%), APC (25.3%), SMAD4 (22.8%), MET (16.8%), CTNNB1 (15.6%) and PIK3CA (10.8%) were the major mutated potential therapeutic targets. KRAS mutation (43.2 Vs. 32.6%) was more prevalent in pancreatobiliary subtype, while TP53 (58.6 Vs 35.1), APC (36.9 Vs 10.8), SMAD4 (28.2 Vs 16.2), MET (21.7 Vs 10.8) and CTNNB1 (19.5 Vs 10.8) were more prevalent in intestinal subtype. WNT signaling pathway was the major altered pathway in intestinal subtype. These mutated genes and pathways may be targeted with currently available drugs and may be explored for future development of targetable agents to improve the disease course in patients of AC.


Subject(s)
Ampulla of Vater/pathology , Biomarkers, Tumor/genetics , Common Bile Duct Neoplasms/epidemiology , Genetic Predisposition to Disease , High-Throughput Nucleotide Sequencing/methods , Mutation , Adult , Aged , Aged, 80 and over , Ampulla of Vater/metabolism , Common Bile Duct Neoplasms/genetics , Common Bile Duct Neoplasms/pathology , Female , Follow-Up Studies , Humans , India/epidemiology , Male , Middle Aged , Prevalence , Prognosis
8.
BMC Res Notes ; 13(1): 316, 2020 Jul 02.
Article in English | MEDLINE | ID: mdl-32616011

ABSTRACT

OBJECTIVE: CD4 T lymphocytes are the most widely used cellular markers to assess the course of HIV infection, clinical staging and, monitoring the effect of antiretroviral therapy. The regional reference range for Eastern, Central and Western development region of Nepal had already been established whereas the same was still lacking in Mid-western and Far-western development region. The objective of this study was to establish reference range of CD4 T lymphocyte in the remaining two development regions and finally the national reference range using data from previous study. RESULTS: The average values (mean ± SD) of CD4 and CD3 T cell in present study was (819 ± 294) cells/µl and (1546 ± 532) cells/µl, respectively. The absolute CD4 T cell (914 ± 303) and CD3 T cell (1671 ± 560) count in female were significantly higher than those from male, CD4 (757 ± 270) and CD3 (1465 ± 499) (p value-0.000). National reference value of CD4 was determined to be (798 ± 335) cells/µl for healthy Nepalese adults.


Subject(s)
CD4 Lymphocyte Count/standards , Adolescent , Adult , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Nepal , Reference Values , Young Adult
9.
J Thyroid Res ; 2020: 6935724, 2020.
Article in English | MEDLINE | ID: mdl-32426104

ABSTRACT

PURPOSE: The primary aim of this study was to determine the incidence of estrogen receptor α (ERα), estrogen receptor ß (ERß), and human epidermal growth factor receptor 2 (HER-2) expression in various subtypes of thyroid carcinoma (TC) of follicular origin and the secondary aim was to correlate the expression with various clinicopathologic prognostic factors. METHODS: Immunohistochemistry analysis was performed on archival paraffin-embedded tissue sections (1991-2016). ERα, ERß, and HER-2 expressions were correlated with clinicopathologic prognostic factors, disease recurrence, and overall survival (OS). RESULTS: A total of 264 TC patients were included in the study. Incidences of ERα, ERß, and HER-2 were 8.1 vs 16.3 vs 13.9% (p=0.15), 26.6 vs 11.5 vs 36.1% (p=0.002), and 12.9 vs 2.9 vs 0% (p=0.003) in papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), and poorly differentiated thyroid carcinoma (PDTC), respectively. Overall ERα had significant correlation with distant metastases (0.038) and in case of PDTC with multicentricity (p=0.037). ERß had significant correlation with lymph node metastases (p=0.023) in FTC. HER-2 correlated with tumor size (p=0.027) only on univariate analysis. OS did not correlate with expression of any receptor. CONCLUSION: ERα, ERß, and HER-2 have differential expression and prognostic implications in different TC subtypes.

10.
FEBS Lett ; 594(8): 1339-1353, 2020 04.
Article in English | MEDLINE | ID: mdl-31930486

ABSTRACT

Knocking out a chromatin factor often does not alter the transcription of its binding targets. What explains the observed disconnect between binding and effect? We hypothesize that this discrepancy could be associated with the role of chromatin factors in maintaining genetic and epigenetic integrity at promoters, and not necessarily with transcription. Through re-analysis of published datasets, we present several lines of evidence that support our hypothesis and deflate the popular assumptions. We also tested the hypothesis through mutation accumulation assays on yeast knockouts of chromatin factors. Altogether, the proposed hypothesis presents a simple explanation for the global discord between chromatin factor binding and effect. Future work in this direction might fortify the hypothesis and elucidate the underlying mechanisms.


Subject(s)
Chromatin/metabolism , Genome, Fungal , Saccharomyces cerevisiae/genetics , Chromatin/genetics , Gene Ontology , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Transcription Initiation Site
11.
Biochem Mol Biol Educ ; 48(3): 227-235, 2020 05.
Article in English | MEDLINE | ID: mdl-31899597

ABSTRACT

Undergraduate laboratory courses, owing to their larger sizes and shorter time slots, are often conducted in highly structured modes. However, this approach is known to interfere with students' engagement in the experiments. To enhance students' engagement, we propose an alternative mode of running laboratory courses by creating some "disorder" in a previously adopted structure. After performing an experiment in the right way, the students were asked to repeat the experiment but with a variation at certain steps leading to the experiment being done the "wrong" way. Although this approach led to fewer experiments being conducted in a semester, it significantly enhanced the students' involvement. This was also reflected in the students' feedback. The majority of students preferred repeating an experiment with a variant protocol than performing a new experiment. Although we have tested this inquiry-based approach only for an undergraduate laboratory course in molecular biology, we believe such an approach could also be extended to undergraduate laboratory courses of other subjects.


Subject(s)
Genetics/education , Learning , Molecular Biology/education , Curriculum , Escherichia coli , Humans , India , Laboratories , Microbiology/education , Research , Students , Universities
12.
Pathophysiology ; 27(1): 3-13, 2020 Dec.
Article in English | MEDLINE | ID: mdl-34321716

ABSTRACT

Hepatitis B virus (HBV) infects the liver, causing cirrhosis and cancer. In developed countries, five international guidelines have been used to make a decision for the management of patients with chronic HBV infection. In this review, since the guidelines were established by clinical and epidemiological data of developed countries, we aimed to evaluate whether (1) HBV patient profiles of developing countries are similar to developed countries, and (2) which guideline can be applicable to resource-limited developing countries. First, as an example of the most recent data of HBV infections among developing countries, we evaluated the national HBV viral load study in Nepal, which were compared with the data from other developing countries. In Nepal, the highest number of patients had viral loads of 20-2000 IU/mL (36.7%) and belonged to the age group of 21-30 years; HBV epidemiology in Nepal, based on the viral loads, gender, and age groups was similar to those of not only other developing countries but also developed countries. Next, we reviewed five international HBV treatment guidelines of the World Health Organization (WHO), American Association for the Study of Liver Diseases (AASLD), National Institute for Health and Care Excellence (NICE), European Association for the Study of the Liver (EASL), and Asian Pacific Association for the Study of the Liver (APASL). All guidelines require the viral load and alanine aminotransferase (ALT) levels for decision making. Although four guidelines recommend elastography to assess liver cirrhosis, the WHO guideline alternatively recommends using the aspartate aminotransferase (AST)-to-platelet ratio index (APRI), which is inexpensive and conducted routinely in most hospitals. Therefore, in resource-limited developing countries like Nepal, we recommend the WHO guideline for HBV treatment based on the viral load, ALT, and APRI information.

13.
World J Oncol ; 10(3): 142-150, 2019 Jun.
Article in English | MEDLINE | ID: mdl-31312281

ABSTRACT

BACKGROUND: Epidermal growth factor receptor (EGFR) mutation is the most frequent mutation tested in lung cancer for targeted therapy in the era of personalized medicine. Knowledge about EGFR mutation is constantly expanding regarding its frequency, clinicopathological association, advancements in testing methodology and sample requirement. We investigated EGFR mutation frequency in non-small cell lung cancer (NSCLC) in North Indian patients and evaluated its diagnostic performance in cytological samples. METHODS: Molecular EGFR testing was done in 250 cases of NSCLC by both real-time polymerase chain reaction (PCR) (Therascreen) and mutation-specific EGFR immunohistochemistry (IHC). Thirty cases had both cytology samples and biopsy including 20 pleural effusions and 10 fine-needle aspirates. EGFR mutation concordance between pleural effusion and biopsy was studied. RESULTS: EGFR mutation was overall 31.6% in NSCLC with 36.5% in adenocarcinoma and 15% in squamous cell carcinoma. L858R mutation accounted for 50.7% and DEL19 for 39.3% of total EGFR mutations. Complex mutations were seen in 2% of cases. Sensitivity of mutation-specific EGFR IHC was 48.3% and specificity was 92.3%. L858R showed higher sensitivity (55% vs. 33.3%) but similar specificity (93.2% vs. 91.3%) compared to DEL19. EGFR mutation was successful in 95% of pleural effusion and showed 83.3% concordance with tissue biopsy. CONCLUSIONS: EGFR mutation frequency in North Indian patients was comparable to that of Asia-Pacific region and showed a similar pattern of histological distribution. EGFR mutation in squamous cell carcinomas is increasingly recognized which was 15% in our study. Mutation-specific EGFR IHC shows variable but generally low sensitivity and considering its significant pre- and post-analytical variables, it should be highly discouraged in patient management. Cytological samples may not only serve as suitable alternative but may be complementary to tissue biopsies.

14.
Mutat Res ; 816-818: 111674, 2019 11.
Article in English | MEDLINE | ID: mdl-31330366

ABSTRACT

Gallbladder carcinoma (GBC) is the most aggressive gastrointestinal malignancy throughout the world, with wide geographical variance. It is the subtype of biliary tract malignancy that has the poorest prognosis and lower survival among all biliary tract malignancies. Various factors are associated with GBC pathogenesis such as environmental, microbial, metabolic and molecular. Chronic inflammation of gallbladder due to presence of gallstone or microbial infection (eg. Salmonella or H. pylori) results in sustained production of inflammatory mediators in the tissue microenvironment, which can cause genomic changes linked to carcinogenesis. Genetic alterations are one of the major factors, associated with aggressiveness and prognosis. Researches have been done to explore suitable biomarker for early diagnosis and identify altered molecular pathways to develop appropriate biomarkers for early diagnosis, therapy and predicting prognosis. Different agents for targeted therapy against actionable mutations of molecules like EGFR, VEGF, mTOR, HER2, PDL-1, PD-1, MET, PI3K, N-cadherin, VEGFR, MEK1 and MEK2 are being tried. Despite these advancements, there is dismal improvement in the survival of GBC patients. Genetic aberrations other than actionable mutations and epigenetic modification including aberrant expressions of micro-RNAs, are also being studied both as diagnostic biomarker and therapeutic targets. Complex pathogenesis of GBC still needs to be unfolded. In this review we focus on the molecular pathogenesis of GBC elucidated till date along with future directions that can be explored to achieve better management of GBC patients.


Subject(s)
Gallbladder Neoplasms/genetics , Gallbladder Neoplasms/pathology , Signal Transduction/genetics , Biomarkers, Tumor/genetics , Epigenesis, Genetic/genetics , Humans , MicroRNAs/genetics , Prognosis
15.
Plant Cell Environ ; 42(3): 874-890, 2019 03.
Article in English | MEDLINE | ID: mdl-30187931

ABSTRACT

Plants code for a multitude of heat stress transcription factors (Hsfs). Three of them act as central regulators of heat stress (HS) response in tomato (Solanum lycopersicum). HsfA1a regulates the initial response, and HsfA2 controls acquired thermotolerance. HsfB1 is a transcriptional repressor but can also act as co-activator of HsfA1a. Currently, the mode of action and the relevance of the dual function of HsfB1 remain elusive. We examined this in HsfB1 overexpression or suppression transgenic tomato lines. Proteome analysis revealed that HsfB1 overexpression stimulates the co-activator function of HsfB1 and consequently the accumulation of HS-related proteins under non-stress conditions. Plants with enhanced levels of HsfB1 show aberrant growth and development but enhanced thermotolerance. HsfB1 suppression has no significant effect prior to stress. Upon HS, HsfB1 suppression strongly enhances the induction of heat shock proteins due to the higher activity of other HS-induced Hsfs, resulting in increased thermotolerance compared with wild-type. Thereby, HsfB1 acts as co-activator of HsfA1a for several Hsps, but as a transcriptional repressor on other Hsfs, including HsfA1b and HsfA2. The dual function explains the activation of chaperones to enhance protection and regulate the balance between growth and stress response upon deviations from the homeostatic levels of HsfB1.


Subject(s)
Heat-Shock Response/physiology , Plant Proteins/physiology , Repressor Proteins/physiology , Solanum lycopersicum/metabolism , Transcription Factors/physiology , Electrophoresis, Gel, Two-Dimensional , Solanum lycopersicum/growth & development , Solanum lycopersicum/physiology , Plants, Genetically Modified , Real-Time Polymerase Chain Reaction
16.
Trends Biochem Sci ; 43(11): 896-907, 2018 11.
Article in English | MEDLINE | ID: mdl-30269981

ABSTRACT

Ubiquitin-like proteins (UBLs) belong to the protein family whose members share a globular beta-grasp fold structure. The archetypal member, ubiquitin, is known for its function in proteasome-mediated protein degradation. UBLs have been shown to play several crucial roles besides protein turnover, including DNA damage response, cell cycle control, cellular signaling, protein trafficking, and innate immunity activation. In the past few years, accumulating evidence illustrates that four UBLs, namely, ubiquitin, SUMO, Hub1, and Sde2, are involved in eukaryotic pre-mRNA splicing. They modify the spliceosomes and promote splicing by adding new surfaces for intermolecular interactions, thereby refining the outcome of gene expression. In this review article, we highlight recent discoveries with an emphasis on the emerging roles of UBLs in splicing regulation.


Subject(s)
RNA Precursors/genetics , RNA Splicing/genetics , RNA, Messenger/metabolism , Ubiquitin/metabolism , Ubiquitins/metabolism , Animals , Humans , RNA, Messenger/genetics
17.
Curr Genet ; 64(4): 777-784, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29299619

ABSTRACT

The occurrence of spliceosomal introns in eukaryotic genomes is highly diverse and ranges from few introns in an organism to multiple introns per gene. Introns vary with respect to their lengths, strengths of splicing signals, and position in resident genes. Higher intronic density and diversity in genetically complex organisms relies on increased efficiency and accuracy of spliceosomes for pre-mRNA splicing. Since intron diversity is critical for functions in RNA stability, regulation of gene expression and alternative splicing, RNA-binding proteins, spliceosomal regulatory factors and post-translational modifications of splicing factors ought to make the splicing process intron-specific. We recently reported function and regulation of a ubiquitin fold harboring splicing regulator, Sde2, which following activation by ubiquitin-specific proteases facilitates excision of selected introns from a subset of multi-intronic genes in Schizosaccharomyces pombe (Thakran et al. EMBO J, https://doi.org/10.15252/embj.201796751 , 2017). By reviewing our findings with understandings of intron functions and regulated splicing processes, we propose possible functions and mechanism of intron-specific pre-mRNA splicing and suggest that this process is crucial to highlight importance of introns in eukaryotic genomes.


Subject(s)
Alternative Splicing/genetics , Introns/genetics , RNA Precursors/genetics , RNA Splicing/genetics , DNA-Binding Proteins/genetics , Humans , RNA Stability/genetics , Schizosaccharomyces/genetics , Spliceosomes/genetics , Ubiquitin/genetics
18.
EMBO J ; 37(1): 89-101, 2018 01 04.
Article in English | MEDLINE | ID: mdl-28947618

ABSTRACT

The expression of intron-containing genes in eukaryotes requires generation of protein-coding messenger RNAs (mRNAs) via RNA splicing, whereby the spliceosome removes non-coding introns from pre-mRNAs and joins exons. Spliceosomes must ensure accurate removal of highly diverse introns. We show that Sde2 is a ubiquitin-fold-containing splicing regulator that supports splicing of selected pre-mRNAs in an intron-specific manner in Schizosaccharomyces pombe Both fission yeast and human Sde2 are translated as inactive precursor proteins harbouring the ubiquitin-fold domain linked through an invariant GGKGG motif to a C-terminal domain (referred to as Sde2-C). Precursor processing after the first di-glycine motif by the ubiquitin-specific proteases Ubp5 and Ubp15 generates a short-lived activated Sde2-C fragment with an N-terminal lysine residue, which subsequently gets incorporated into spliceosomes. Absence of Sde2 or defects in Sde2 activation both result in inefficient excision of selected introns from a subset of pre-mRNAs. Sde2 facilitates spliceosomal association of Cactin/Cay1, with a functional link between Sde2 and Cactin further supported by genetic interactions and pre-mRNA splicing assays. These findings suggest that ubiquitin-like processing of Sde2 into a short-lived activated form may function as a checkpoint to ensure proper splicing of certain pre-mRNAs in fission yeast.


Subject(s)
DNA-Binding Proteins/metabolism , Introns , RNA Splicing , Schizosaccharomyces pombe Proteins/metabolism , Schizosaccharomyces/genetics , Ubiquitin/metabolism , DNA-Binding Proteins/genetics , Genomic Instability , Humans , RNA Precursors/genetics , RNA, Fungal/genetics , RNA, Fungal/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Schizosaccharomyces/metabolism , Schizosaccharomyces pombe Proteins/genetics , Spliceosomes
19.
Clin Immunol ; 183: 207-212, 2017 10.
Article in English | MEDLINE | ID: mdl-28390966

ABSTRACT

The IL-17/1L-23 axis is important in the pathogenesis of spondyloarthropathy. Innate cells produce IL-17 in addition to Th17 cells. We studied the frequencies of natural killer (NK) (total, CD56bright, CD56dim, perforin+ and granzyme+), NK-T, γδ-T, and IFN-γ+, IL-17+ NK and γδ-T cells in peripheral blood (PB) and synovial fluid (SF) of ReA/uSpA patients. PB from 45 patients and paired SF from 39 patients were studied, together with PB from 18 healthy controls (HC). The frequency of γδ-T cells was decreased (p<0.05) while IL-17 producing NK and γδ-T cells were increased (p<0.05) in PB of patients as compared to HC. In SF, CD56bright NK cells were increased (p<0.001) but had reduced expression of perforin and granzyme (p<0.0001) as compared to PB. Frequency of IL-17+, IFN-γ+ NK and γδ-T cells was higher in SF as compared to PB (p<0.05). We suggest that innate cells by producing pro-inflammatory cytokines may contribute to pathogenesis.


Subject(s)
Interferon-gamma/metabolism , Interleukin-17/metabolism , Killer Cells, Natural/metabolism , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Spondylarthropathies/pathology , T-Lymphocytes/metabolism , Adolescent , Adult , Arthritis, Reactive/pathology , Female , Humans , Immunity, Innate , Interferon-gamma/genetics , Interleukin-17/genetics , Killer Cells, Natural/immunology , Male , Prohibitins , Synovial Fluid , Young Adult
20.
BMC Infect Dis ; 16(1): 450, 2016 Aug 26.
Article in English | MEDLINE | ID: mdl-27566067

ABSTRACT

BACKGROUND: Accurate and prompt diagnosis of HIV and syphilis simultaneously has reinforcing effect on their control program because of their prevalent co-infection. Availability of a simple user-friendly two-pronged and affordable detection tools brings down the cost of health care. They are important in the antenatal clinics, with added opportunity for intervention and prevention of mother to child transmission. In cooperation with rapid test kit manufacturers, SD Bioline, NPHL and NCASC, an evaluation of commercially available HIV/syphilis Duo rapid test kit (SD Bioline) to assess its performance and operational characteristics was done in the present study. METHOD: A prospective laboratory-based cross sectional study was conducted at a large Women's Hospital. Ten thousand pregnant women, visiting the Hospital for antenatal care or for delivery, were enrolled in study. Tests were performed by the SD Bioline HIV/Syphilis Duo kit as well as national algorithm for HIV and syphilis diagnosis which were considered gold standard. Sensitivity, Specificity, positive predictive value and negative predictive value along with kappa coefficient were calculated for the kit under evaluation. RESULT: The sensitivity, specificity, Negative predictive value and Positive predictive value of the kit for HIV diagnosis were 100 % (95 % CI 83.18-100 %, 99.96-100 %, 83.18-100 %, and 99.96-100 %, respectively). Kappa value was found to be 1.0. Out of total cases, results of 9985 (99.85 %) cases were concordant with National algorithm for syphilis diagnosis. Thirteen (0.13 %) cases were found false positive while two were false negative. The sensitivity of the kit for syphilis diagnosis was found to be 95.45 % (95 % CI 84.86-98.74 %) and specificity was 99.87 % (95 % CI; 99.78-99.92 %). Positive predictive value was 76.36 % (95 % CI; 63.65-85.63 %) and Negative predictive value was 99.89 % (95 % CI; 99.39-99.99 %). Kappa value was found to be 0.85. CONCLUSION: The performance characteristics of SD Bioline HIV/Syphilis duo kit were found almost concordant with the kits being used for HIV and Syphilis diagnosis separately. Its implementation in antenatal clinics/VCTs could be an added opportunity for simultaneous diagnosis of HIV and syphilis.


Subject(s)
Coinfection/diagnosis , HIV Infections/diagnosis , Pregnancy Complications, Infectious/diagnosis , Reagent Kits, Diagnostic , Syphilis/diagnosis , Cross-Sectional Studies , Female , Humans , Nepal , Pregnancy , Prospective Studies , Sensitivity and Specificity
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